erickson



J. ERICKSON.

- MEASURED SERVICE TELEPHONE SYSTEM.

' APPLICATION FILED JUNE 7. I916. 1,330,019. Patented Feb. 3,1920.

2 SHEETS-SHEET I.

1 aafs7[[ Hit/1 7 J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED JUNE 1. 19M.

1,330,01 9. Patented Feb. 3,1920.

2 SHEETSSHEET 2.

UNITED sm es PATENT OFFICE.

JOHN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOR'TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MEASURED-SERVICE TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Feb. 3, 1920.

Application filed June 7, 1916. Serial No. 102,184.

To (4Z5 whom it may concern:

Be it known that 1, JOHN ERIOKSON, a

citizen of the United States of America, and

a resident of Ghicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Measured-Service Telephone Systems, of which the following is. a specification.

My invention relates in general to measured service telephone systems but is concerned more particularly with measured service telephone systems of the automatic type in which the connections are estab lished by automatic switches controlled by the individual subscribers.

In systems of the above character the measured service equipment usually comprises either coin collecting devices or meters. Whatever the device used, it ordinarily performs its function but once for each successful originating call made over its associated line. If a coin collecting device is used, one coin or token is collected for .each call; if a meter, one call is registered against the calling subscriber when the called party answers.

In every exchange there are certain subscribers who are prone to take advantage of the ordinary measured service system by prolonging their conversations to an undue length, and it is evident that where the charges are based on a certamrate per conversation, regardless of its length, they may do so with impunity. It is desirable, therefore, to provide in connection with a measured service system, means of some klnd for limiting the length of conversations, both to protect the telephone company from impositions on the part of the subscribers, and to secure a more equitable distribution of the charges.

The present invention 'PIOVIClGS ZLD apparatus whereby after a predetermined time interval a distinctive toneinay be thrown on a connection to warn the talking subscribers that their conversation has contin nod for the maximum time allowed and that additional toll must be collected. In case the subscribers persist in holding the connection, agencies are brought into play shortly afterward which result in the collection of an additional charge from the .alling subscriber.

The particular means which I employ in accomplishing the foregomg and other useful ends will be fully described hereinafter, reference being had to the accompanying drawings, in which Figures 1 and 2 show diagrammatically a complete circuit connection between a calling substation A and a called substation A in a system embodying the principles of my invention, while Figs. 3 and 4 illustrate certain mechanical parts of the conversation limiting apparatus. The central oilice apparatus used in establishing the complete connection above referred to comprises the individual line switch C (Fig. 1) and the connector switch F (Fig. For the purpose of simplifying the drawings and the explanation, the selector switches, which are understood to be included in a system of any size, are omitted.

Referring now to Fig. 1., the substation A may be of any suitable or approved type although as shown it is similar to the substation shown in the British patent to Martin, No. 1419 of 191.0. Among other details it comprises the receiver 2, transmitter 23, induction coil a, hook switch 5, ringer 6 and condenser 7 Being an automatic substation there is also provided a calling device comprising essentially a pair of impulse springs 8 and 9 controlled by the impulse wheel 10 through the medium of a finger hole dial (not shown).

Associated with the substation A is shown diagrammatically a coin collecting device which comprises among other details a polarized relay 12 in serieswith one of the line conductors, a set of contact springs 13 controlled by the relay 12 and adapted to render the substation A inoperative for talking purposes, and suitable coin controlled means including a coin chute (not shown) for restoring the substation to operative condition. A similar coin collecting device has been shown and described in U. S. Letters'Patent #1,062,387, granted to me on May 20, 1913, and consequently no extended description will be given herein.

The line conductors 14 and 15 of the substation A are connected at the exchange to the ind' 'idual line switch C which is of the general type of line switch disclosed in the British patent to James, #526,301 of 1906; being. however, of the particular type shown in U. S. Letters Patent $51,078,690, granted Jan. 17, 1912, to Frank Newforth. Since line switches of the above type are Well known and form no part of my invention an extended description will not be given. It will suflice to say here that through the medium of line switch C the line of substation A when calling is given access to a plurality of trunk lines extending to connector switches.

The master switch D is of the general typeof master switch disclosed in the above mentioned British patent to James, #526,301

of 1906; being, however, more nearly of the particular type disclosed in the British patent to Martin, #1419 of 1910, also previously referred to. As is well known, the function of the master switch is to maintain the plungers of all idle line switches in position before the terminals of an idle trunk line. I

One of these trunk lines is indicated in the drawings by reference characters 4.0, 41, and 42 and terminates in the connector switch F (Fig. 2), which is of the general type of connector switch disclosed in U. S. Letters Patent #815,176, granted March 13, 1906, to Keith, Erickson, and Erickson; being, however, of the particular type dis closed in the British patent to the Automatic Telephone Mfg. 00., #2270 of 1914. connector switch of the foregoing type may be given access to a group of subscribers lines and is operable in response to digits of a called number to establish connection with any line in the group. I

The substation A and the line switch C may be similar, respectively, to the substation A and the line switch C, which have already been briefly described.

Considering now the conversation limiting apparatus shown diagrammatically in Fig. 1, it will be seen that the upper trunk conductor 40 includes the right hand winding of the electro-polarized relay 45, while both conductors 4:0 and 42 include spring contacts of the reversing relay 19. Each trunk line is provided'with a pair of similar relays, whose operation will be fully described hereinafter. With each pair of re lays is associated a device comprising, in the case of the trunk line shown, the solenoid 60, plunger 61, and contact springs 5659, inclusive. The solenoids associated with a group1 of trunk lines are preferably mounted toget er, as shown in Fig. 3, in order that their plungers may be controlled by a com mon time mechanism. A soft iron mounting plate 63, bent to the shape shown in Fig. 4, is secured in suitable manner to the support 66. Each of the solenoids 60 is provided. with a heel piece 67 through the nedium of which it is secured to the mounting plate 63. A soft iron roller 62, fitting loosely in the curved portion of the mounting plate 63, iscarried bythe shaft 65, which in turn is rotatably supported by bearings at each end of the mounting plate, one of these bearings being indicated by reference character 64. Each solenoid is provided with a plunger 61 which fits loosely in a brass sleeve or tube which carries the solenoid winding and which extends up through the heel piece 67 to prevent sticking between the plunger and heel piece. The parts are so disposed that the solenoid plungers 61 are in light contact with the roller 62. The

shaft is constantly rotated at a slow rate by clock work or other suitable means (not shown). The several sets of contact springs controlled by the solenoid plungers are not shownin Figs. 3 and 4 but it will be understood from a consideration of the diagrammatic showing in Fig. 1 that each set is suitably mounted above its associated plunrent generator B, the ringing interrupter I,

and the busy signaling machine Q are of the ordinary type and perform the same func tions as the same named pieces of apparatus in other automatic exchanges.

The apparatus having been briefly described, I will now proceed to a description ofthe operation of the same. Inasmuch as a great deal of the automatic equipment is old and well known, having been fully described in the publications previously rcferred to, the operation of such equipment will be described in a. moreor less general manner.

Referring to Fig. 1, when the calling, sub scriber at siilbstation A removes his receiver to initiate the call, an energizing circuit is completed over the line conductors 11 and 15 for the line relay 16 of the line switch C. Upon attracting its armature, the line relay 16 closes a circuit for the pull-in winding 17. operates both the plunger arm. 21 and the cut-off armature 22'; the former through the medium of its plunger (not shown) forcing the bank springs 3033, inclusive, into en gagement, respectively, with contacts 3 l37, inclusive; and the latter disconnecting the line conductors 15 and 1 1, respectively, from ground and from the line relay 16. By the cup; lent of bank springs 30 and 33,respect 'cly, with contacts 3 1 and 37, the l 1e conductors 14 and 15 are extended -via trunk enercloses a circuit for the slowncting rel iiase relay 101. Upon energizing,.the release relay 101 completes a holding circuit for the Upon energizing, the pull-in winding ger in position to be controlled thereby, all

line switch 0 which may be traced as fol lows: ground at G, cont-act springs 119, conductor &1, contact 35, bank spring 31, and holding winding 18 to battery B. Since the line relay 16 is slow-acting, it retains its armature to maintain the pull-in winding energized until after the above holding circuit has been established. A branch of the holding circuit extent-is from bank spring 31 by wa i of conductor 19 to multiple test contacts in the banks of connector switches having access to the line of substation A where by a. ground potential on these test contacts the said line is made busy. By the engagement of bank spring 32 with contact 36 the master switch D is operated in well known manner to advance the plungers of all. the remaining idle line switches into position before the terminals of the neXt idle trunk line.

It should be noted at this point that the trunk conductor 40 includes the winding 17 of the electro-polarized relay 45. Current is also flowing in the polarizing winding 16 from the grounded conductor 41 to the batteiy B. Neither winding of relay 15 is sufficiently powerful of itself to operate the armature, but it requires the combined effect of both windings. Since at this time the magnetizing effects of the two windings are in opposition the relay 15 is not operated. At the substation A the polarized relay 12, being in series with one side of the line, is energized and operates its armature to the position shown in the drawing.

The foregoing operations whereby the line conductors ll and 15 have been QXtBHt e-c through to the line relay 100 of the con-nector F have taken place in response to the removal of the receiver at substation A. The calling subscriber may now manipulate his dial in accordance with the first digit of the desired number, thereby separating momentarily the impulse springs 8 and 9 a number of times and interrupting each time the energizing circuit of the line relay 100 As a result of these interruptions of its circuit the line relay 100 is deenergized corrcsponrh ing number of times and sends at each deenergizaation an impulse from ground G to the slow-acting relay 103 and the vertical magnet 10-1 in series, side switch wiper 115 being in its first position. The vertical mag net in response to these impulses steps up the switch shaft until the wipers 130, 131, and 132 stand opposite the horizontal level of bank-contacts in which is located the termin'al of the line of subtation A. lay 103 energized in series with the cal magnet and, being slow-acting, r its armature during the series of impul maintain a circuit from ground G to the private magnet 107. At the end of the series of impulses the relay 103 decnergizes and breaks the circuit of the private magnet,

which latter controls the side switch wipers to advance them to their second position in the usual manner.

The subscriber at substation A may now operate his dial in accordance with the final digit of the required number, resulting as before in deenergizations of the line relay 100. Now, however, side switch wiper 115 being in its second position, the line relay sends impulses to the slow-acting relay 103 in series with the rotary magnet 105. The rotary magnet operates in response to these impulses to rotate the wipers 130, 131, and 132 until they rest, respectively, upon bank contacts 133, 131-, and 135, these contacts foming the terminal of the line of sub station A in the bank of connector F.

The relay 103 and the private magnet 107 are energized during the last series of impulses as before, the latter disconnecting the line wipers during rotation and controlling the side switch wipers at the end of the series of impulses to advance them to their third position, it being assumed that the line of substation A was idle when called.

As side switch wiper 116 comes into engagement with its third position contact point, a circuit is completed for the'holding winding of line switch C as follows: ground at G side switch wiper 116 (in third position), wiper 131, bank contact 134,

and holding winding 18 to battery B. n73,

the attraction of the cut-off armature 22 the line conductors of substation A are disconnected, respectively, from ground and from the line relay 16. It is understood that the holding winding 18 is not suiticiently powerful to operate the plunger arm 21, Ground at G also extends to multiples of bank contact 134: in the banks of other connectors of the group, thereby making the line of substation A busy to other calls. By the engagement. of side switch wipers 117 and 118 with their third position contact points the connection between the calling and called lines is completed. By the cn 'a 'ement of side switch wi oer with its third position contact point, a circuit is completed for the ringing relay 108 in seri with the interrupter 1, whereby ringing current is projected intermittently out over the line of substation A to operate the sig nal in bridge thereof.

The subscriber at substation A has now established the desired connection with substation A and the bell at the latter substation is being rung to attract the attention of the called subscriber. When the called subscriber removes his receiver from the hook a circuit is completed for the double wound back bridge relay 102 in the well known manner. Upon attracting its armature, relay 102 closes a circuit for the ing cut-off relay 106 which relay locks itself to ground at G and also opens the circuit of the ringing relay 108, thereby stopping the ringing operation.

As a further result of the ci'iergizati on of the back bridge relay the incoming trunk conductors 40 and 42 are reversedas regard their connection to the windings of the line relay 100. The direction of current flow in the calling line is therefore reversed with several important results which will now be described. At the substation A the polarized relay 12 reverses the position of its armature thereby rendering the. telephone instrun'ient inoperative for talking purposes by closing the springs 13. The telephone is not completely disabled, however, for although the transmitter is short-circuited, the receiver is only shunted by a resistance so that the calling subscriber will be able to tell whether or not he has the right number. Finding that the desired connection has been obtained the calling subscriber now restores his telephone instrument to operative condition again by depositing one or more coins in the usual manner and is then able to converse without further effort. The complete talking circuit has been drawn in heavy' lines and will be apparent without additional description.

The talking connection between thecalling and called subscribers having been established, it is to be presumed that the operation of the time limit device associated with the trunk line used was initiated also, and such is the fact. When the direction of cur rent flow in the calling line was reversed upon the response of the called subscriber, not only was the polarized relay 12 at the substation A operated with the i .sults mentioned, but at the exchange the electro-polarized relay 45 is enabled to attract its armature, since its two windings new assist each other. When its armature is fully attracted the winding 47 is shortcircuited and the relay is maintained in operated position by the winding 46 alone. An energizing circuit for the solenoid 60 may now .be traced I as follows: ground at G, contact springs 54 and 55, contact springs 51 and50, and winding of solenoid 60 to battery B. As a result ofthe magnetic field set up by current in the solenoidthe plunger 61 and the roller 62 attract each other, and since the roller is retating the plun er 61 will be slowly raised up through the center of the solenoid by magnetic friction. After a certain predetermined time interval the plun er 61 forces spring 59 into engagement wit-1 spring 57. The spring 58 is adJuSted to follow spring 57 for a short distance so that for a few sec-- ends a tone from the buzzer M is projected out over the connected lines to inform the :.:ubseribers that their conversation has nearly reached the limit. Upon further movement of the plunger 61- the contact springs 56 and 57 come into engagement, thereby closing the following circuit: ground at G, secondary winding of the buzzer M, contact springs 59, 57, and 56, and winding of slow-acting relay 49 to battery B. Upon attracting its armature, relay 4L9 reverses the trunk conductors 40 and 42 in an obvious manner and near the end of its stroke separates the contact springs 54.- and 55, thereby breaking the energizing circuit of solenoid 60. The plunger 61 immediately falls by gravity to its normal. position and breaks the energizing circuit of relay 49. Since relay 49 is slow-acting it retains its armature an instant in order to insure the complete retraction oi the plunger 61. When relay it) finally deenergizes, the trunk conductors t0 and 4 2 are connected straight through again, the energizing circuit of the solenoid is again completed, and the plunger 61 begins its ascent up through the core of the solenoid again.

It will be understood that the purpose of the momentary energizatien of relay 49 after a predetermined time, is to effect by a reversal of the. line current the operation of the polarized relay 12 at the calling substae tion, whereby the telephone instrument is again rendered inoperative for talking purposes. Whenthe calling subscriber hears the tone from the buzzer M on the line, he at once gets another coin ready to deposit, provided, of c0urse,-that he wishes to continue the conversation. Being thus Warned in advance but little time need be lost and consequently the interruption of the conversation is not seriously objectionable. Of course, the deposit must not be made until after the tone leaves the line (and relay 49 has restored) or the coin would be wasted. The time limit device at the exchange continues to operate as long as the connection is held, mementsurily reversing the line current at in" tervals and requiring each time an additional deposit by the calling subscriber.

Yfheu the conversation is finished both subscribers will han up their receivers. By the .rep'lacen'ient oft e receiver at substation A the energizing circuit of line relay 1100 is broken. Upon deenergizing, the line relay opens the energizing circuit of the slow-acting release relay 101, which latter relay, upon deenergizing, closes a cricuit for the release magnet 109 and also removes ground from the holding circuit e-Xtending back to line switch C. By the closure of the release magnet circuit the connector F is restored to normal position in the usual and well known n'iauner. By the ren'ioval of ground from the holding circuit the holding winding 18 of line switch C is deenergized and the plunger is withdrawn from the bank. As a further result the relay a5 is denergized, thereby stopping the operation of the time limit ape paratus. All the equipment usedwill then have been restored to normal in readiness for other calls.

It will be seen from the foregoing that I have devised a simple'and efficient apparatus for use in connection with a measured service system whereby conversations may be limited to a definite time and additional charges collectedon all conversations which exceed the time limit.

While I have found it convenient in explaining my invention to show a certain specific embodiment thereof, I am well aware that changes may be made in order to adapt the same to other types of measured service systems. I do not, therefore, wish to limit myself to the exact form shown but desire to include and have protected by Letters Patent all forms and modifications of my invention which may come within the scope of the appended claims.

lVhat Iclaim as my invention is:

1. In a telephone system, a calling and a called line, means for connecting said lines, a reverse current controlled device for rendering the calling telephone inoperative for talking purposes, means comprising a coin collecting device for restoring the calling telephone to operative condition, a battery for supplying talking current, a relay for reversing the current flow in the calling line to require the deposit of a coin before conversation can begin, and a second relay for momentarily reversing the current flow in the calling line again after a predetermined time to require the deposit of another coin.

2. In a telephone system, a calling and a called line, means for connecting said lines, a reverse current controlled device for rendering the calling telephone inoperative for talking purposes, means comprising a coin collecting device for restoring the calling telephone to operative condition, a battery for supplying talking current, a relay for reversing the current flow in the calling line to require the deposit of a coin before conver sation can begin, a second relay for momentarily reversing the current flow in the calling line again after a predetermined time to require the deposit of another coin, a device for producing an audible tone, and means for connecting said device with the calling line whenever an additional coin is required to notify the calling subscriber.

3. In a telephone system, a callin and a called line, means including an automatic progressively movable svvi ch for connecting said lines, a reverse current controlled device for rendering the calling telephone inoperative for talking purposes, means comprising a coin collecting device for restoring the calling telephone to operative condition, a battery for supplying talking current, a relay for reversing the current flow in the calling line to require the deposit of a coin before conversation can begin, a second relay for momentarily reversing the current flow in the calling line again after a predetermined time to require the deposit of another coin, and means for notifying the calling subscriber when an additional coin is to be deposited.

4. In a telephone system, a calling and a called line, automatic switches at the exchange for uniting said lines in a talking circuit comprising two inductiveiy connected sections, a device at the calling substation for assessing a charge against the calling subscriber at the beginning of conversation, and automatic mechanism included in the calling section of the talking circuit for controlling said device to assess an additional charge at intervals thereafter.

5. In a telephone system, a calling and a called line, automatic switches at the eX- change for uniting said lines in a talking circuit comprising two inductively connected sections, a device at the calling substation for assessing a charge against the calling subscriber at the beginning of conversation, automatic mechanism included in the calling section of the talking circuit for controlling said de ice to assess an additional charge at intervals thereafter, and a signaling device adapted for connection to the calling line under control of said mechanism to notify the calling subscriber when an additional charge is to be assessed.

6. In a telephone system, a calling and a called line, means for connecting said lines, a device at the substation requiring the deposit of a coin by the calling subscriber at the beginning of conversation, and time mechanism including a frictionally driven movable element for controlling said device to require the deposit of additional coins at intervals thereafter.

7. In a telephone system, a calling and a called line, means for connecting said lines, a device at the substation requiring the de posit of a coin by the calling subscriber at the beginning of conversation, mechanism at the exchange for controlling said device to require the deposit of an additional coin, a continuously operating power shaft, and means including an electromagnetic clutch for causing said shaft to actuate said mechanism at intervals duringthe conversation.

8. In a telephone system, the combination with connecting means comprising a plurality of trunk lines, of mechanism associated therewith for dividing conversatlons into periods of predetermined length, said mechanism comprising a driven shaft, and an electromagnetic clutch controlled device associated with each trunk line and operated from said shaft for notifying connected subscribers when the said periods have expired.

9. In a telephone system, the combination with connecting means comprising a plurality of trunk lines, of mechanism associated therewith for dividing conversations into periods of predetermined length, said mechanism comprising a common power source, and a device associated with each trunk line and mechanically operated from said common source for notifying connected subscribers when each period has expired.

10. An electric circuit switchin combination with a controller therefor, said controller having a plunger, a wheel associated with said plunger, means for bringing said plunger and wheel into engagement, means for rotating said wheel while thus in en agenient with the plunger to ove the .atter, and a toll assessing device controlled over the said circuit.

Signed by me at Chicago, Cook county, State of Illinois, this 1st day of June, 1916.

JOHN ERICKSON. 

